fix (dynamic content): fields do not occupy the entire text control space

Author: [email protected]

src/components/dynamic-content-control/editor.scss

@@ -42,6 +42,7 @@
 
 	.components-base-control {
 		margin-bottom: 0;
+		flex: 1;
 
 		.components-base-control__field {
 			margin-bottom: 0;